This is just an excuse for ignorance and the annoying habit people have of repeating something they heard but don't understand.

I think it's right to correct it because when people misuse this phrase, it isn't gaining a new meaning--it's making it meaningless. Why apples? The comparison to apples adds no information or nuance.

Like when there's a story about police corruption, and someone says "they're just a few bad apples, not all cops are bad." Again, why compare them to apples? Why not just say a few bad cops?

This isn't words/phrases changing meaning, it's losing meaning.